Electron removal from hydrogen atoms by impact of multiply charged nuclei

Abstract

The boundary-corrected continuum intermediate state (BCIS) method is used to compute total cross sections for electron capture by seven heavy nuclei (${\mathrm{Li}}^{3+}$, ${{\mathrm{Be}}}^{4+}$, $\mathrm{B}^{5+}$, $\mathrm{C}^{6+}$, $\mathrm{N}^{7+}$, $\mathrm{O}^{8+}$ and $\mathrm{F}^{9+}$) from atomic hydrogen ${{\mathrm{H}}}(1s)$ at impact energies 20–3000 keV/amu. In all the cases, regarding the exit channel, we compute the cross sections $Q_{if}$ for the specific individual final bound states $f=(n,l,m)$ of hydrogen-like ions, where throughout $i=(1,0,0)=1s$ (the ground state of the target, H). The maximal value of the principal quantum number n has been taken to be $n _\mathrm{max}= 4,\,5$ and 6 for ${\mathrm{Li}}^{3+},$ ${\mathrm{Be}}^{4+}$ and $\mathrm B^{5+},$ respectively, as well as $n_\mathrm{max} = 7$ for $\mathrm{C}^{6+},$ $\mathrm{N}^{7+},$ $\mathrm{O}^{8+}$ and $\mathrm{F}^{9+}.$ All the sub-levels (l, m) for every n are included in the computations. Further, the summed cross sections $Q_{i,{{\Sigma }}}={\sum }_fQ_{if}$ for all the final (f) states are reported. In $Q_{i,{{\Sigma }}},$ the state-selective cross sections $Q_{if}$ contain the exact contributions from the final levels with $n\le n_\mathrm{max}.$ The collective yield from the final states with $n>n _\mathrm{max}$ is approximated by the Oppenheimer $n^{-3}$ scaling. To put the present results into perspective, comparisons are made with the boundary-corrected first Born (CB1) and the continuum distorted wave-eikonal final state (CDW-EFS) methods. Both the BCIS and CDW-EFS methods belong to the group of the second-order asymmetric methods for charge-exchange. Most importantly, the available experimental data are used to assess the relative performance of the BCIS method for total cross sections summed over all final states. This type of total cross section databases from our computations can find useful applications in several neighboring disciplines (plasma physics, astrophysics, new energy sources in fusion research) as well as in ion transport physics of relevance to, e.g., radiotherapy in medicine.

Graphic abstract